Climb-up assist structure for mower unit

ABSTRACT

A mower unit configured to be supported to a work vehicle at a position between front wheels and rear wheels, comprises a mower deck; at least one blade supported by the mower deck; a climb-up assist member in which an inclined surface is formed for assisting the wheels in climbing over the mower unit; and a connecting device for detachably connecting the climb-up assist member to the mower unit in a service position in which the inclined surface assists the wheels in climbing over the mower unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/042,871 filed Mar. 5, 2008 which claims priority to Japanese PatentNo. 2007-093500 filed Mar. 30, 2007 and Japanese Patent No. 2007-139341filed May 25, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mower unit configured to be attachedin a position between the front wheels and the rear wheels of a workvehicle, and more specifically relates to a climb-up assist structurethat is provided to such a mower unit.

2. Description of the Related Art

A mower climb-up assist structure for a work vehicle is known in whichan elongated running board extending to the front and rear of the mowerdeck, and in which an inclined part is integrally formed at both thefront and rear end parts for raising and lowering of the wheels inrelation to the mower unit, is integrally fitted to the mower unit so asto straddle the mower deck in the front and rear direction (e.g., JP51-28524).

In the configuration described above, since the running board isintegrally fitted to the mower unit, a vehicle wheel can easily becaused to climb over the mower unit by moving any of the front and rearwheels of the work vehicle to the running board. As a result, there isno need to spend effort to bring the mower unit in between the frontwheels and the rear wheels from beside the work vehicle, and the mowerunit can be easily positioned between the front wheels and the rearwheels of the work vehicle. There is also no need to spend effort totake the mower unit out from between the front wheels and the rearwheels of the work vehicle, and the mower unit can be easily removed inone of the front and rear directions of the work vehicle from betweenthe front wheels and the rear wheels of the work vehicle.

However, in the configuration described above, the elongated runningboard that straddles the mower deck in the front and rear direction isintegrally fitted to the mower unit, and the overall structure of themower unit therefore increases in size, and the weight or cost of themower unit as a whole also increases.

When a common mower unit not provided with a running board is modifiedto a climb-over specification provided with a running board, anelongated running board must be welded to the mower deck, bolt holes forbolting the running board to the mower deck must be formed, or otherprocessing must be performed, and because painting must be redone afterthis processing, a large amount of labor is required for themodification. Conversely, when the specifications of the common mowerunit must be modified from the climb-over specifications, the mower deckmust then be replaced, the connecting holes formed in the mower deckmust be filled in and repainted, and other work must be performed, and alarge amount of labor is therefore required for the specificationchange. The cost increases particularly when the mower deck is replaced.

SUMMARY OF THE INVENTION

An object of the present invention is to overcome at least one of thedrawbacks of the prior art described above.

A mower unit configured to be supported to a work vehicle at a positionbetween front wheels and rear wheels comprises the following:

a mower deck;

at least one blade supported by the mower deck;

a climb-up assist member in which an inclined surface is formed forassisting the wheels in climbing over the mower unit; and

connecting means for detachably connecting the climb-up assist member tothe mower unit in a service position in which the inclined surfaceassists the wheels in climbing over the mower unit.

In an embodiment, the mower deck preferably has a rear wall, and theservice position of the climb-up assist member is preferably a positionin which the climb-up assist member is disposed behind a rear wall ofthe mower deck.

In an embodiment, the connecting means preferably comprises a turnupportion that is formed at a lower edge of the mower deck and foldedupwardly and outwardly of the mower deck, and an engaging portionprovided to the climb-up assist member, for releasably engaging theturnup portion.

In an embodiment, the mower unit preferably comprises connecting meansfor detachably connecting the climb-up assist member to the mower unitin a storage position.

In an embodiment, the mower unit preferably comprises an anti-slipportion disposed in a vicinity of a rear end portion of the climb-upassist member, for preventing wheels of the work vehicle from slippingwhen the work vehicle climbs over the mower deck.

In an embodiment, a forward portion of the climb-up assist memberforwardly of the anti-slip portion is preferably formed so as to tiltdownward and to the rear.

In an embodiment, the mower unit preferably comprises a transmissionmechanism for driving the blade; and a transmission cover for coveringthe transmission mechanism from above; wherein the mower deck is aside-discharge-type mower deck in which an internal passage forfunctioning as a passage for cut grass transport is formed in a frontupper portion of the mower deck, and the front upper portion is formedto bulge upwardly along a left-right width of the mower deck; and a topsurface of the front upper portion, and a top surface of thetransmission cover are at substantially the same height.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall side view of the tractor that shows a state inwhich the mower unit is installed in a tractor;

FIG. 2 is a partial side view of the relevant parts that shows thepositional relationship between the mower unit and the climb-up assistmember;

FIG. 3 is a plan view of the relevant parts that shows the positionalrelationship between the mower unit and the climb-up assist member;

FIG. 4 is a perspective view of the relevant parts that shows theattachment-detachment structure of the climb-up assist member withrespect to the mower unit;

FIG. 5 is a longitudinal side view of the relevant parts that shows theoperation of the climb-up assist member;

FIG. 6 is a side view of the relevant parts that shows the connectingstructure between the second link and the second bracket;

FIG. 7 is a perspective view of the relevant parts that shows theconnecting structure between the second link and the second bracket;

FIG. 8 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 9 is a partial side view showing the relevant parts of thestructure according to another embodiment;

FIG. 10 is a perspective view showing the relevant parts of thestructure according to another embodiment;

FIG. 11 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 12 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 13 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 14 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 15 is a plan view showing the relevant parts of the structureaccording to another embodiment;

FIG. 16 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 17 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 18 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 19 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 20 is a longitudinal side view showing the relevant parts of thestructure according to another embodiment;

FIG. 21 is a perspective view showing the connecting means according toanother embodiment;

FIG. 22 is a perspective view showing the connecting means according toanother embodiment;

FIG. 23 is a side view showing the connecting means according to anotherembodiment;

FIG. 24 is an overall side view of the tractor that shows a state inwhich the mower unit is installed in the tractor;

FIG. 25 is a partial side view of the relevant parts that shows theextension portion and the anti-slip portion;

FIG. 26 is a plan view of the relevant parts that shows the extensionportion and the anti-slip portion;

FIG. 27 is a perspective view of the relevant parts that shows theextension portion and the anti-slip portion;

FIG. 28 is a partial side view of the relevant parts that shows theoperation of the anti-slip portion;

FIG. 29 is a partial side view showing the relevant parts of thestructure according to another embodiment; and

FIG. 30 is a partial side view showing the relevant parts of thestructure according to another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment in which the present invention is applied to a tractor 1as an example of a work vehicle will be described hereinafter based onthe drawings. A number of embodiments will be described, butcombinations of the characteristics of one embodiment with thecharacteristics of another embodiment are also included in the scope ofthe present invention.

FIG. 1 is an overall side view of the tractor 1. In the tractor 1 asshown in FIG. 1, a vehicle body frame 7 is formed in which a front frame2, an engine 3, a clutch housing 4, a middle frame 5, and a transmissioncase 6 are connected so as to be positioned in sequence from the frontside of the vehicle body. A front axle case 9 provided with a pair ofleft and right front wheels 8 is supported at the front-half portion ofthe vehicle body frame 7 so as to be capable of rolling, and an enginebonnet 10 or the like for covering the engine 3 and other componentsfrom above is also provided. A pair of left and right rear wheels 11 orthe like is provided at the rear-half portion of the vehicle body frame7, and an operating unit 14 provided with a steering wheel 12, anoperating chair 13, and other components is formed at the rear-halfportion.

Drive force from the engine 3 is transmitted to the input shaft (notshown) of a hydraulic static transmission device (hereinafterabbreviated as HST) 15 connected to the front part of the transmissioncase 6, via a main clutch (not shown) or the like provided inside theclutch housing 4. The drive force after conversion by the HST 15 istaken off from the output shaft (not shown) of the HST 15 as drive forcefor travel, and is transmitted to a gear-type transmission device (notshown) provided inside the transmission case 6. The drive force afterconversion by the gear-type transmission device is branched inside thetransmission case 6 into drive force for the front wheels and driveforce for the rear wheels, and the drive force for the front wheels istransmitted to the left and right front wheels 8 via a front-wheeltransmission system (not shown) provided inside the transmission case 6,the front axle case 9, or the like. The drive force for the rear wheelsis transmitted to the left and right rear wheels 11 via a rear-wheeltransmission system (not shown) provided inside the transmission case 6.The unconverted drive force from the input shaft of the HST 15 istransmitted as drive force for work via a work transmission system (notshown) provided inside the transmission case 6 to a first drive forcetakeoff shaft 16 provided to the rear end part of the transmission case6, and a second drive force takeoff shaft 17 provided to the bottom partof the transmission case 6.

The rear part of the transmission case 6 is provided with a pair of leftand right lift arms 18 that are pivotally driven in the verticaldirection by the operation of a hydraulic cylinder (not shown) providedinside the rear part of the transmission case 6, a first link mechanism19 for pivoting up and down in the vertical direction in conjunctionwith the pivotal driving the lift arms 18, and other components. Thefirst link mechanism 19 is provided with a pair of right and left lowerlinks 20 or the like formed so as to allow attachment and detachment ofa rotary cultivator or other implement (not shown).

In other words, the implement mounted to the first link mechanism 19 canbe raised and lowered through the operation of the hydraulic cylinder.The first drive force takeoff shaft 16 is connected to the input shaftof the implement via a transmission shaft (not shown) or the like,whereby the drive force for work that is transmitted to the first driveforce takeoff shaft 16 can be fed to the implement.

Although not shown in the drawing, the hydraulic cylinder is configuredso that the operation state of a control valve for controlling the flowof operating fluid to the hydraulic cylinder is switched in conjunctionwith the pivoting operation of a raising and lowering lever provided tothe operating unit 14, whereby the operating state is switched to anoperating state that is in accordance with the operating position of theraising and lowering lever.

As shown in FIGS. 1 and 2, a second link mechanism 22 for suspending andsupporting a mower unit 21 or other implement disposed between (in thelower middle portion of the tractor 1) the left and right front wheels 8and the left and right rear wheels 11 in the tractor 1 so as to becapable of being raised and lowered is detachably installed in thevehicle body frame 7. The second link mechanism 22 is provided with apair of left and right first links 23 that extend from the front part ofthe vehicle body frame 7 to the front end part of the mower unit 21, apair of left and right second links 24 that extend from the middleportion of the vehicle body frame 7 to the rear part of the mower unit21, and other components. The second links 24 are linked to the left andright lower links 20 via a linking mechanism 25.

The linking mechanism 25 is composed of a rotation shaft 26 oriented tothe left and right that is supported by the vehicle body frame 7 so asto be able to rotate in relative fashion; a pair of left and right firstlinking arms 27 that extend towards the front of the vehicle body fromthe rotation shaft 26; a pair of left and right second linking arms 28that extend upward from the rotation shaft 26; a pair of left and rightcoupling arms 29 provided to the rear part of the transmission case 6; apair of left and right first linking rods 30 for linking the left andright first linking arms 27 to the free ends of the corresponding secondlinks 24; a pair of left and right second linking rods 31 for linkingthe left and right second linking arms 28 to the corresponding couplingarms 29; and other components. The left and right coupling arms 29 aresupported by a support axle 32 of the corresponding lower links 20 so asto be able to pivot in relative fashion. Contacting tabs 29A forpartially contacting the upper edges of the corresponding lower links 20are formed in curved fashion on the top parts of the left and rightcoupling arms 29.

In other words, when the mower unit 21 or other implement is installedin the lower middle portion of the tractor 1, a configuration is adoptedin which the mower unit 21 or other implement can be raised and loweredby the operation of the hydraulic cylinder.

A single third linking arm 33 that extends toward the rear of thevehicle body is integrally mounted to the rotation shaft 26. A receivingstopper 34 for preventing the downward pivoting of the left and rightsecond links 24 by stopping the upward pivoting third linking arm 33 isprovided in the vehicle body frame 7. The receiving stopper 34 issupported by the vehicle body frame 7 so that rotation is possible abouta vertical axis. A plurality of levels of stopping parts (not indicatedby reference symbols) set so that the receiving height of the thirdlinking arm 33 varies in the peripheral direction is formed in thecylindrical lower edge part of the receiving stopper 34. When thereceiving stopper 34 is rotated about the vertical axis from thisconfiguration, the stopping part for stopping the third linking arm 33is changed, and the height position of stopping of the third linking arm33 by the receiving stopper 34 is changed, i.e., the height position atwhich the receiving stopper 34 prevents the downward pivoting of theleft and right second links 24 is changed.

In other words, the third linking arm 33 and the receiving stopper 34constitute a cutting height adjustment mechanism 35 for adjusting thecutting height of the mower unit 21 by changing the position of thelower limit height of the mower unit 21.

In the linking mechanism 25, the left and right lower links 20 and theleft and right coupling arms 29 are configured to have a contact on oneside, whereby downward pivoting of the left and right lower links 20 bythe operation of the hydraulic cylinder is allowed when downwardpivoting of the left and right second links 24 is prevented by thereceiving stopper 34.

In the mower unit 21 as shown in FIGS. 1 through 3, a transmissionmechanism 38 for blade driving is provided to the top part of a mowerdeck 37 having three blades 36 that are rotationally driven clockwise asviewed in a plane about a corresponding vertical rotation shaft 36A, anda pair of left and right transmission covers 39 for covering the leftand right end parts of the transmission mechanism 38 from above aredetachably attached to the top part of the mower deck 37. In the mowerdeck 37, the front upper part 37A thereof is formed so as to expandupward along the left-right width of the mower deck 37 so that the mowerdeck 37 has an internal passage 37B for transporting cut grass in thefront upper part 37A. A discharge vent 37C is formed in the right end ofthe mower deck 37, and a discharge cover 40 is also attached.

In other words, the mower unit 21 has a side-discharge-typeconfiguration in which the grass cut by the three blades 36 isdischarged from the discharge vent 37C at the right end via the internalpassage 37B of the front upper part 37A in the mower deck 37 by theconveying airflow generated by the rotation of the blades 36.

In the mower deck 37, four rolling wheels 41 are distributed for thefront, rear, left, and right. A roller 42 is provided at the center ofthe front part of the mower deck 37. The free end parts of thecorresponding first links 23 of the second link mechanism 22 aredetachably linked to a pair of left and right first brackets 43 forsupporting the roller 42. A pair of left and right second brackets 44 towhich the free end parts 24A of the corresponding second links 24 of thesecond link mechanism 22 is detachably linked by a pin are provided tothe rear part of the mower deck 37.

In the transmission mechanism 38, an input shaft 46 by which the driveforce from the second drive force takeoff shaft 17 of the tractor 1 istransmitted is provided to the rear part of a transmission case 45disposed in the center of the mower deck 37. The drive force transmittedto the input shaft 46 is transmitted to an output shaft 47 provided tothe lower part of the transmission case 45 via a transmission mechanism(not shown) provided inside the transmission case 45. The rotation shaft36A provided in the center of the mower deck 37, as well as a drivepulley 48, are connected to the output shaft 47 so as to integrallyrotate. The rotational force of the drive pulley 48 is transmitted via atransmission belt 50 to driven pulleys 49 that rotate integrally withthe rotation shafts 36A that are provided at the left and right of themower deck 37.

In other words, the transmission mechanism 38 is configured according toa belt transmission system in which the drive force from the seconddrive force takeoff shaft 17 of the tractor 1 is transmitted by a beltto the rotation shafts 36A of the three blades 36, and the three blades36 are rotationally driven.

The reference numeral 51 in FIG. 3 indicates a tension pulley that istensed by a tension spring 52. The input shaft 46 is connected to thesecond drive force takeoff shaft 17 of the tractor 1 via an extensibletransmission shaft 53 and a universal joint 54.

As shown in FIGS. 1 through 5, the left and right transmission covers 39are formed by folded steel plates so as to have a ceiling wall 39A, anoutside wall 39B, and a rear wall 39C. In the ceiling walls 39A, aninverted L-shaped foot portion 55 is welded that comes in contact withthe upper surface of the mower deck 37 when the transmission covers 39are attached to the mower deck 37. In the front part of the ceiling wall39A, an engaging fixture 57 is provided for detachably engaging to acorresponding ring-shaped engaged fixture 56 provided to the front upperpart 37A of the mower deck 37. The engaging fixture 57 is composed of,among other components, an operating part 57A capable of pivotingforward and backward, and a hook-shaped engaging part 57B composed of aleaf spring that changes position between a disengaged position and aengage position with respect to the engaged fixture 56 on either side ofa dead point, in conjunction with the pivoting of the operating part57A. In the rear walls 39C, a pair of left and right elongated holes 39Dengaged with corresponding engaging pins 58 that are provided facingrearward in the mower deck 37 is formed so as to extend in the verticaldirection. The engaging pins 58 are secured to a total of four receivingplates 59 provided one pair each to the rear side on the left and rightof the mower deck 37.

In other words, a connecting mechanism that enables attachment anddetachment of the transmission covers 39 with respect to the mower deck37 is formed by the aforementioned engaged fixture 56, the engagingfixture 57, the left and right elongated holes 39D, the left and rightengaging pins 58, and the left and right receiving plates 59. In a statein which the transmission covers 39 are attached to the mower deck 37,the front surfaces of the rear walls 39C of the transmission covers 39join with the back surfaces of the corresponding receiving plates 59,the lower edges of the elongated holes 39D in the transmission covers 39join with the corresponding engaging pins 58, and the front ends of theceiling walls 39A are set so as to join with the front upper part 37A ofthe mower deck 37. Through this configuration, the left and righttransmission covers 39 can be stably attached to the mower deck 37, andwhen the left and right transmission covers 39 are attached to the mowerdeck 37, the upper end surface of the front upper part 37A in the mowerdeck 37 is positioned at substantially the same height as the upper endsurfaces of the ceiling walls 39A in the left and right transmissioncovers 39.

As shown in FIGS. 1 through 6, a pair of left and right climb-up assistmembers 60 are installed in the tractor 1 and provided with inclinedsurfaces 60A for assisting the climbing up of the front and rear wheels8, 11 with respect to the mower unit 21. The climb-up assist members 60are made of steel plates folded into an L shape as viewed from the sideso as to have long, gently sloping inclined surfaces 60A. The inclinedsurfaces 60A are formed on the elongated side, and the short side isdetachably connected to the mower unit 21 via a first connecting means61 or a second connecting means 62.

The first connecting means 61 detachably connects the climb-up assistmembers 60 to the mower unit 21 in a service position in which theinclined surfaces 60A assist the climbing up of the wheels 8, 11 withrespect to the mower unit 21, and is composed of a folded part 37Eformed at the lower edge 37D of the mower deck 37, and an end edge part(engaging part) 60B on the short side of the climb-up assist members 60,wherein the end edge part 60B is configured to detachably engage thefolded part 37E from above. The folded part 37E is integrally formedalong the entire lower edge 37D by the folding of the lower edge 37D ofthe mower deck 37 upward and to the outside of the mower deck 37 throughpress working when the mower deck 37 is formed.

The second connecting means 62 detachably connects the climb-up assistmembers 60 to the mower unit 21 in the storage position, and is composedof a pair of left and right connecting bolts 63 welded so as to extendtowards the rear in the rear walls 39C of the transmission covers 39;butterfly nuts 64 threaded onto the connecting bolts 63; and a pair ofleft and right concave parts 60C formed in the short sides of theclimb-up assist members 60 so as to open downward.

The service position is the position in which the climb-up assistmembers 60 are disposed with respect to the mower unit 21 so that theinclined surfaces 60A of the climb-up assist members 60 are placed in astate of extending across the ground surface in front from a positionthe vicinity of the front end upper part of the mower deck 37, or in astate in which the left and right wheels 8, 11 that climb up theinclined surfaces 60A face the corresponding transmission covers 39 in astate in which the inclined surfaces 60A extend across the groundsurface behind from a position in the vicinity of the rear end upperpart of the mower deck 37.

The storage position is the position in which the climb-up assistmembers 60 are disposed on the mower unit 21 so that the climb-up assistmembers 60 are positioned between the rear ends of the correspondingtransmission covers 39 and the rear end of the mower deck 37 in theupper part of the mower deck 37.

When the mower unit 21 is moved from the abovementioned configuration tothe position between the left and right front wheels 8 and the left andright rear wheels 11 in the tractor 1, the connection in the storageposition by the second connecting means 62 is released to detach theclimb-up assist members 60 from the storage position, and the climb-upassist members 60 are connected to the mower unit 21 via the firstconnecting means 61 so as to be positioned in the service position onthe rear side, after which the front wheels 8 climb up the inclinedsurfaces 60A of the corresponding climb-up assist members 60, and climbonto the rear upper part of the mower deck 37 when the tractor 1 ismoved forward so that the front wheels 8 of the tractor 1 face towardsthe corresponding climb-up assist members 60.

When the tractor 1 is moved further forward after the upward climb, thefront wheels 8 climb onto the corresponding transmission covers 39 fromthe rear upper part of the mower deck 37, and move to the front upperpart 37A of the mower deck 37 from the corresponding transmission covers39, after which the front wheels 8 descend towards the ground surfacefrom the front upper part 37A of the mower deck 37.

The left and right front wheels 8 thereby climb over the mower unit 21,and the mower unit 21 is positioned between the left and right frontwheels 8 and the left and right rear wheels 11.

Conversely, when the mower unit 21 is removed from between the left andright front wheels 8 and the left and right rear wheels 11 in thetractor 1, the connection of the climb-up assist members 60 in thestorage position by the second connecting means 62 is released to detachthe climb-up assist members 60 from the storage position, and theclimb-up assist members 60 are connected to the mower unit 21 via thefirst connecting means 61 so as to be positioned in the service positionon the rear side, after which the rear wheels 11 climb up the inclinedsurfaces 60A of the corresponding climb-up assist members 60, and climbonto the rear upper part of the mower deck 37 when the tractor 1 ismoved forward so that the rear wheels 11 of the tractor 1 face towardsthe corresponding climb-up assist members 60.

When the tractor 1 is moved further forward after the upward climb, therear wheels 11 climb onto the corresponding transmission covers 39 fromthe rear upper part of the mower deck 37, and move to the front upperpart 37A of the mower deck 37 from the corresponding transmission covers39, after which the rear wheels 11 descend towards the ground surfacefrom the front upper part 37A of the mower deck 37.

The left and right rear wheels 11 thereby climb over the mower unit 21,and the mower unit 21 is positioned behind the tractor 1.

In other words, the mower unit 21 can easily be taken in and out frombetween the left and right front wheels 8 and the left and right rearwheels 11 without the need for the labor of carrying the mower unit 21into position between the left and right front wheels 8 and the left andright rear wheels 11 from beside the tractor 1, or carrying the mowerunit 21 out from between the left and right front wheels 8 and the leftand right rear wheels 11.

When the mower unit 21 is positioned between the left and right frontwheels 8 and the left and right rear wheels 11, the left and rightclimb-up assist members 60 are placed in the service position to therear, and the left and right front wheels 8 are caused to ascend theinclined surfaces 60A of the corresponding climb-up assist members 60and to climb over the mower unit 21 as a result of forward travel inwhich the positional relationship between the left and right climb-upassist members 60 and the left and right front wheels 8 is easilyrecognized. The mower unit 21 is therefore easily climbed over.

Furthermore, in a state in which the climb-up assist members 60 arepositioned in the service position at the rear, the elongated gentlysloping inclined surfaces 60A of the climb-up assist members 60 extendacross the ground surface behind from a position in the vicinity of theupper rear end part of the mower deck 37, and climbing up over the mowerunit 21 can therefore be smoothly performed in a stable riding state inwhich no instability is felt.

After the mower unit 21 is climbed over, the climb-up assist members 60are removed from the service position and positioned in the storageposition, making it possible to prevent situations in which the climb-upassist members 60 make contact with the ground and resist travel orsteering, or damage the area being mowed and cause other problems,during work travel in which the mower unit 21 is connected to thetractor 1.

During climbing of the mower unit 21, the climb-up assist members 60 areconnected to the mower unit 21 via the first connecting means 61.Therefore, even when the mower unit 21 is pushed out in the directionaway from the climb-up assist members 60 by the front wheels 8 or therear wheels 11 during movement of the left and right front wheels 8 orthe left and right rear wheels 11 from the inclined surfaces 60A of thecorresponding climb-up assist members 60 to the rear upper part of themower deck 37, the mower unit 21 is prevented from moving, along withthe climb-up assist members 60 that are prevented from moving by thepressure of the front wheels 8 or the rear wheels 11. Adverse effects onthe smoothness of climbing over the mower unit 21 due to separation ofthe mower unit 21 from the climb-up assist members 60 can thereby beprevented.

As indicated by the dashed line in FIG. 3, when the climb-up assistmembers 60 are connected to the mower unit 21 via the first connectingmeans 61 so as to be positioned in the service position on the frontside, the rear wheels 11 or the front wheels 8 climb up the inclinedsurfaces 60A of the corresponding climb-up assist members 60 and climbonto the front upper part 37A of the mower deck 37 when the tractor 1 ismoved in reverse so that the rear wheels 11 or the front wheels 8 of thetractor 1 face the corresponding climb-up assist members 60.

When the tractor 1 is also moved in reverse after climbing up, the rearwheels 11 and the front wheels 8 move onto the correspondingtransmission covers 39 from the front upper part 37A of the mower deck37 and descend from the corresponding transmission covers 39 to the rearupper part of the mower deck 37, and then descend towards the groundsurface from the rear upper part of the mower deck 37.

The left and right rear wheels 11 or the left and right front wheels 8thereby climb over the mower unit 21, and the mower unit 21 ispositioned between the left and right front wheels 8 and the left andright rear wheels 11, or in front of the tractor 1.

In other words, even when the climb-up assist members 60 are positionedin the service position on the front side, there is no need for thelabor of placing the mower unit 21 in between the left and right frontwheels 8 and the left and right rear wheels 11 from beside the tractor1, or carrying the mower unit 21 out from between the left and rightfront wheels 8 and the left and right rear wheels 11, and the mower unit21 can be easily moved in and out between the left and right frontwheels 8 and the left and right rear wheels 11.

As shown in FIGS. 2 through 4, in the left and right transmission covers39, a round bar member 65 is welded facing to the left and right in aposition below the engaging part 57B in the ceiling wall 39A. Throughthis configuration, when the wheels 8, 11 of the tractor 1 roll from thetransmission covers 39 to the front upper part 37A of the mower deck 37,deformation of the engaging part 57B due to running over of the engagingpart 57B can be prevented, and the engaging part 57B and the engagedfixture 56 can be prevented from disengaging from each other due to thisdeformation.

As shown in FIGS. 2 through 5, in the left and right transmission covers39, a reinforcing member 66 extending to the front and rear of theceiling wall 39A is welded at the inner end of the ceiling wall 39A.This configuration makes it possible to suppress misalignment of theleft and right wheels 8, 11 to the left and right in relation to theleft and right transmission covers 39 when the tractor 1 climbs over themower unit 21, while increasing the strength of the left and righttransmission covers 39.

In the mower deck 37 as shown in FIGS. 2 through 4, plate-shapedanti-slip members 67 are provided in front of the left and righttransmission covers 39 in the front upper parts 37A of the mower deck37. The left and right anti-slip members 67 can thereby be used asreferences when the left and right front wheels 8 are caused to climbover the mower unit 21 in forward travel, and the left and right frontwheels 8 can be easily and reliably caused to climb over the mower unit21 by forward travel. Slippage of the wheels 8, 11 with respect to themower deck 37 that can occur when the wheels 8, 11 of the tractor 1descend onto the ground from the front upper part 37A of the mower deck37 can also be suppressed by the left and right anti-slip members 67. Asa result, the mower unit 21 can be prevented from being abruptly pushedto the rear by slippage.

In the mower deck 37 as shown in FIGS. 2 through 7, the upper rear edgeparts 44 a of the left and right second brackets 44 are curved so as toapproach the front of the machine body towards the lower side. In theleft and right second links 24, the free end parts 24A connected by apin to the corresponding second brackets 44 are formed so that, whenviewed from above, the parts have a substantial bracket shape that openstowards the front of the machine body, and the front parts of the leftand right side wall portions 24 a thereof are formed so as to separatefrom each other towards the front. The front parts of the left and rightside wall portions 24 a extend further downward than the rear parts, andthe lower front edge parts 24 b of the extending front parts are formedin a forward-tilting orientation positioned to the front towards theupper sides thereof. When the aforementioned cutting height adjustmentmechanism 35 is operated, and the lower-limit height position of theleft and right second links 24 is set to the height position forattachment to the mower unit 21, the left and right lower front edgeparts 24 b in the left and right second links 24, and the upper rearedge parts 44 a of the left and right second brackets 44 are set to aheight position at which contact can be made.

According to this configuration, in a case in which the mower unit 21 isattached to the lower middle portion of the tractor 1, the tractor 1 ismoved forward so that the left and right front wheels 8 thereof climbover the mower unit 21 via the left and right climb-up assist members 60in a state in which the lower-limit height of the left and right secondlinks 24 is set to the height position for attachment to the mower unit21. At this time, when misalignment occurs within the allowable range inthe left-right direction between the left and right second brackets 44and the free end parts 24A of the left and right second links 24, therearward pressure on the mower unit 21 that occurs when the left andright front wheels 8 descend onto the ground from the front upper part37A of the mower deck 37 can be utilized to cause any of the left andright lower front edge parts 24 b in the left and right second links 24to come in contact in intersecting fashion with the upper rear edgeparts 44 a of the corresponding second brackets 44 without theinconvenience that occurs when the mower unit 21 travels forwardtogether with the forward travel of the tractor 1, and the lower frontedge part 24 b can be slid and guided to the proper position in theleft-right direction by the corresponding upper rear edge parts 44 a.The corresponding second brackets 44 can thereby be reliably andautomatically engaged between the left and right side wall portions 24 aand the free end parts 24A of the left and right second links 24 inconjunction with the climbing over of the mower unit 21 by the tractor1.

After this automatic engagement, the rear ends of the free end parts 24Ain the left and right second links 24 make contact with the upper rearedge parts 44 a of the corresponding second brackets 44, whereuponengaging pins 68 provided to the left and right second links 24, andengaging holes 44 b formed in the left and right second brackets 44 areset so as to face each other. In this facing state, the engaging pins 68fixed in the engagement release position are operated against the urgingof a push spring 70 through engaging with a support member 69, and whenthe engagement with the support member 69 is released, the free endparts 24A of the left and right second links 24 can easily by connectedby the pins to the corresponding second brackets 44.

When the mower unit 21 is removed from the lower middle part of thetractor 1, the engaging pins 68 are engaged with the support member 69against the urging of the push spring 70, after which the free end parts24A in the left and right second links 24 are separated upward from thecorresponding second brackets 44 when the left and right second links 24are pivoted upward by the action of a hydraulic cylinder, and the freeend parts 24A can be positioned at the height position that allows theleft and right rear wheels 11 of the tractor 1 to climb over the mowerunit 21.

Other Embodiments

[1] The work vehicle 1 to which the present invention is applied is notlimited to a tractor insofar as the mower unit 21 can be detachablyprovided between the front wheels 8 and the rear wheels 11 of the workvehicle.

[2] The mower unit 21 may be configured to a rear-dischargespecification in which discharge takes place from a discharge vent 37Cformed at the rear end via a front upper part 37A or other internalpassage 37B in the mower deck 37 through a conveying airflow that isgenerated in conjunction with the rotation of the blades.

[3] The mower unit 21 may be configured to a mulching specification inwhich cut grass that is cut by the blades is circulated inside the mowerdeck 37 and finely cut, and then dropped to the ground surface belowfrom an opening in the bottom of the mower deck 37.

[4] The mower unit 21 may have a shaft transmission configuration inwhich the drive force from the work vehicle 1 is transmitted to therotation shaft 36A of the blades 36 via a bevel gear, a transmissionshaft, or the like.

[5] The mower unit 21 may be configured so that two blades, or four ormore blades, are provided in the mower deck 37.

[6] The mower unit 21 may be configured to have an inclined surface thattilts between the upper rear end part of the mower deck 37 and the upperrear end parts of the transmission covers 39. A mower unit 21 having adifference in level between the front end part of the mower deck 37 andthe front end parts of the transmission covers 39 may be configured tohave an inclined surface that tilts between the upper front end part ofthe mower deck 37 and the upper front end parts of the transmissioncovers 39.

[7] The mower unit 21 may have a configuration in which the folded part37E is not formed in the lower edge 37D of the mower deck 37.

[8] The first connecting means 61 may be configured so that the climb-upassist members 60 are detachably connected to the mower unit 21 bybolts/nuts in the service position.

[9] The first connecting means 61 may be configured so that the climb-upassist members 60 are detachably connected only in the service positionset on the rear side of the mower unit 21, or so that the climb-upassist members 60 are detachably connected only in the service positionset on the front side of the mower unit 21.

[10] The second connecting means 62 may have a releasable engagingconfiguration composed of engaging parts provided to the climb-up assistmembers 60, and an engaged part provided to the mower unit 21.

[11] A configuration may be adopted in which a connecting means 62 isprovided to the work vehicle for setting the storage position of theclimb-up assist members 60, and detachably connecting the climb-upassist members 60 with respect to the work vehicle in the storageposition. An accommodating part for accommodating the climb-up assistmembers 60 so as to allow removal and installation may also be providedto the work vehicle.

[12] As shown in FIG. 8, the climb-up assist members 60 may be formed soas to have a large difference in level between the upper end parts ofthe inclined surfaces 60A and the upper part of the mower deck 37 in theservice position. In this configuration as well, since the climb-upassist members 60 are connected to the mower unit 21 via the firstconnecting means 61 in the service position, when the left and rightfront wheels 8 or the left and right rear wheels 11 roll onto the rearupper part (or front upper part) of the mower deck 37 from the inclinedsurfaces 60A of the corresponding climb-up assist members 60, even whenthe mower unit 21 is pushed away from the climb-up assist members 60 bythe front wheels 8 or the rear wheels 11, the mower unit 21 is preventedfrom moving along with the climb-up assist members 60, whose movement isprevented by the pressure of the front wheels 8 or the rear wheels 11.As a result, the smoothness of the climb-up over the mower unit 21 canbe prevented from being adversely affected by separation of the mowerunit 21 from the climb-up assist members 60.

The reference numeral 71 shown in FIG. 8 indicates a round steelreinforcing member that is welded to the back surfaces of the inclinedsurfaces 60A so as to touch the ground in the service position.

[13] As shown in FIG. 9, the edge parts (engaging parts) 60B on theshort sides of the climb-up assist members 60 may be formed so as toengage with the lower edge 37D of the mower deck 37 from below. In otherwords, in this case, the first connecting means (connecting meansdescribed in claims 1 and 2) 61 is composed of the lower edge 37D of themower deck 37 and the edge parts 60B of the short sides of the climb-upassist members 60. In this configuration as well, when the left andright front wheels 8 or the left and right rear wheels 11 roll onto therear upper part (or front upper part) of the mower deck 37 from theinclined surfaces 60A of the corresponding climb-up assist members 60,even when the mower unit 21 is pushed away from the climb-up assistmembers 60 by the front wheels 8 or the rear wheels 11, the mower unit21 is prevented from moving along with the climb-up assist members 60,whose movement is prevented by the pressure of the front wheels 8 or therear wheels 11. Therefore, the smoothness of climbing over the mowerunit 21 can be prevented from being adversely affected by separation ofthe mower unit 21 from the climb-up assist members 60.

[14] As shown in FIGS. 10 and 11, the climb-up assist member 60 may beprovided so as to be capable of sliding and changing position betweenthe storage position and the service position with respect to the mowerunit 21, and may be capable of being attached and detached in theservice position.

Describing this configuration in more detail, as shown in FIGS. 10 and11, the climb-up assist member 60 is formed from a steel plate having across-sectional shape that is curved into a bracket shape; an engagingpin 60D that protrudes outward to the right is integrally provided atthe end part on the storage position side in the right-side wall; andengaging holes 60E, 60F are formed at the end part on thestorage-position side and the end part on the use-position side,respectively, in the left-side wall.

In the mower unit 21, a guide member 72 formed in a bracket shape asviewed from above is integrally provided to the transmission cover 39(or the mower deck 37); the engaging pin 60D of the climb-up assistmember 60 is slid and guided forward and backward in the right-side wallof the guide member 72; a slit 72A for allowing engagement and releaseof the engaging pin 60D in the service position is formed in theright-side wall; and an engaging pin 72B capable of insertion andwithdrawal with respect to the engaging holes 60E, 60F of the climb-upassist member 60, a spring 72C for urging the engaging pin 72B in theinsertion direction with respect to the engaging holes 60E, 60F, andother components are provided to the end part on the use-position sidein the left-side wall of the guide member 72.

In other words, according to this configuration, the engaging pin 60D ofthe climb-up assist member 60 is inserted into the slit 72A of the guidemember 72 in the service position, and the engaging pin 72B of the guidemember 72 is inserted into the engaging hole 60E on the storage-positionside in the climb-up assist member 60, whereby the climb-up assistmember 60 can be connected to the mower unit 21 (see FIGS. 10 and 11B).

In this connected state in the service position, when the engagement ofthe engaging pin 72B with respect to the engaging hole 60E on thestorage-position side is released against the urging of the spring 72C,the climb-up assist member 60 is allowed to slide and move from theservice position to the storage position, and the climb-up assist member60 can be removed from the mower unit 21. In this state, when theclimb-up assist member 60 is slid to the storage position, the engagingpin 72B of the guide member 72 is engaged in the engaging hole 60F onthe use-position side in the climb-up assist member 60 by the urging ofthe spring 72C. The climb-up assist member 60 can thereby be locked andmaintained in the storage position set at the upper part of the mowerunit 21 (see FIG. 11A).

In the state in which engaging is maintained in the storage position,when the engagement of the engaging pin 72B in the engaging hole 60F onthe use-position side is released against the urging of the spring 72C,the climb-up assist member 60 is allowed to slide from the storageposition to the service position. In this state, the climb-up assistmember 60 is slid to the service position, whereupon the engaging pin72B of the guide member 72 is engaged in the engaging hole 60E on thestorage-position side in the climb-up assist member 60 by the urging ofthe spring 72C. The climb-up assist member 60 can thereby be locked (orengaged) and maintained in the service position in a state of beingextended towards the ground surface in the front and rear direction fromthe upper part of the mower unit 21 (see FIGS. 10 and 11B).

The connecting means (first connecting means) 61 for detachablyconnecting the climb-up assist member 60 to the mower unit 21 in theservice position is composed of the engaging pin 60D provided to theclimb-up assist member 60, the engaging hole 60E on the storage-positionside, the slit 72A provided to the guide member 72, the engaging pin72B, the spring 72C, and other components.

In this configuration, the climb-up assist member 60 has an extensibleconfiguration in which a plurality of plates are connected so as to beable to extend and retract, an elongated inclined surface 60A that ismore easily climbed can be formed by extending the climb-up assistmember 60 in the service position, and the climb-up assist member 60 maybe configured to enable compact storage by retracting the climb-upassist member 60 in the storage position.

[15] As shown in FIGS. 12 and 13, a configuration may be adopted inwhich the climb-up assist member 60 formed by a steel plate in which abent part 60G (see FIG. 12) or a curved part 60H (see FIG. 13) isintegrally formed at one end can be attached and detached with respectto the mower unit 21 in the service position by the engaging andreleasing of the bent part 60G or the curved part 60H with respect to around steel engaging member 73 integrally provided in a left-rightorientation to the mower deck 37.

In this configuration, the connecting means (first connecting means) 61for detachably connecting the climb-up assist member 60 to the mowerunit 21 in the service position is composed of the bent part 60G orcurved part 60H provided to the climb-up assist member 60, and theengaging member 73 provided to the mower deck 37.

[16] As shown in FIGS. 14 through 16, a configuration may be adopted inwhich the climb-up assist members 60 are provided so as to be able toslide to the left and right as well as forward and rearward with respectto the mower unit 21, and the climb-up assist members 60 can be attachedand detached with respect to the mower unit 21 in a storage position setabove the mower unit 21.

Describing this configuration in more detail, as shown in FIGS. 14through 16, the climb-up assist members 60 are formed from steel platesin which a bent part 60K (see FIGS. 14 and 15) or a curved part 60L (seeFIG. 16) is integrally formed at one end.

In the mower deck 37, a round steel support member 74 is provided in aleft-right orientation for supporting the climb-up assist members 60 sothat the climb-up assist members 60 can slide to the left and right, andin the forward-rear direction through the engagement of the bent part60K or curved part 60L. The support member 74 is configured to have alength for slidably guiding the climb-up assist members 60 in theleft-right direction between a facing position towards the inside of thevehicle body in which the climb-up assist members 60 face each other inthe forward-rear direction, and a non-facing position towards theoutside of the vehicle body in which the climb-up assist members 60 donot face each other in the forward-rear direction with respect to thewheels 8, 11 that climb up the mower unit 21.

The service position is set to a position in which the climb-up assistmember 60 is positioned so as to face towards the inside of the vehiclebody, and in which the climb-up assist member 60 extends towards theoutside in the forward-rear direction from the mower unit 21.

The support member 74 and the bent part 60K or curved part 60L of theclimb-up assist member 60 are configured to engage each other so thatthe inclined surface 60A of the climb-up assist member 60 is positionedbetween the mower deck 37 and the support member 74 in a state in whichthe climb-up assist member 60 extends towards the outside in theforward-rear direction from the mower unit 21, whereby attachment anddetachment of the climb-up assist member 60 with respect to the mowerunit 21 are prevented, and to engage each other so that the inclinedsurface 60A of the climb-up assist member 60 is positioned above thesupport member 74 in a state in which the entire climb-up assist member60 is positioned above the mower unit 21, whereby attachment anddetachment of the climb-up assist member 60 with respect to the mowerunit 21 are allowed.

In other words, in this configuration, the climb-up assist member 60 canbe prevented from accidentally separating from the mower unit 21 duringclimbing up of the mower unit 21 in which the climb-up assist member 60is in the service position. When the climb-up assist member 60 needs tobe replaced, the climb-up assist member 60 can be attached and detachedwith respect to the mower unit 21 by pivoting the climb-up assist member60 from the service position to the storage position. Furthermore, afterone of the front and rear wheels 8, 11 has climbed over the mower unit21, when the other wheels 8, 11 approaches the climb-up assist member 60too closely and impedes the pivoting of the climb-up assist member 60from the service position to the storage position, the climb-up assistmember 60 can be pivoted to the storage position by sliding the climb-upassist member 60 from the service position (facing position) to thenon-facing position (see FIG. 15).

[17] As shown in FIG. 17, the service position of the climb-up assistmembers 60 may be set to a position (position of no connection by thefirst connecting means 61) in which the climb-up assist members 60 areadjacent to the mower unit 21 so that the inclined surfaces 60A of theclimb-up assist members 60 extend across the frontward ground surfacefrom the vicinity of the upper front end part of the mower deck 37, orextend across the rearward ground surface from the vicinity of the upperrear end part of the first linking arms 27 in front of or behind themower unit 21, and so that the left and right wheels 8, 11 that climbthe inclined surfaces 60A face towards the corresponding transmissioncovers 39.

[18] The climb-up assist member 60 may be connected to one of the frontand rear ends of the mower unit 21 (mower deck 37) via a support shaftin a left-right orientation so as to be able to pivot between thestorage position above the mower unit 21, and the service position inwhich the climb-up assist member 60 extends to the outside in theforward-rear direction from the mower unit 21, and so that the climb-upassist member 60 can be attached and detached with respect to the mowerunit 21 through insertion and withdrawal of the support shaft in each ofthe storage position and the service position.

[19] As shown in FIG. 18, the climb-up assist member 60 may have afolding configuration in which two plates 75, 76 are connected so as tobe able to flex and extend via a connecting shaft 77, and the climb-upassist member 60 may be connected to one of the front and rear ends ofthe mower unit 21 (mower deck 37) via a support shaft 78 in a left-rightorientation so as to be able to pivot between the storage position abovethe mower unit 21, and the service position in which the climb-up assistmember 60 extends to the outside in the forward-rear direction from themower unit 21.

When the climb-up assist member 60 is endowed with a foldingconfiguration, an elongated inclined surface 60A that is more graduallysloped and easy to climb can be formed by unfolding the climb-up assistmember 60 in the service position (see FIG. 18B). When the climb-upassist member 60 is pivoted between the service position and the storageposition, the climb-up assist member 60 is folded up, whereby theclimb-up assist member 60 is compactly arranged, and the climb-up assistmember 60 can be prevented from coming in contact with the device or thelike installed in the lower middle portion of the work vehicle 1 (seeFIG. 18A).

In other words, it is possible to enhance the ease of operation when theclimb-up assist member 60 is pivoted between the service position andthe storage position while making climbing over the mower unit 21 stableand smooth, with no sense of instability imparted to the operator.

In FIG. 18, a configuration is shown in which the climb-up assist member60 is folded through the use of two plates 75, 76, but anotherconfiguration may also be adopted in which the climb-up assist member 60is folded through the use of three or more plates or the like. In theservice position, an elongated inclined surface 60A that is even moregently sloped and easy to climb may be formed by unfolding the climb-upassist member 60. When the climb-up assist member 60 is pivoted betweenthe service position and the storage position, the climb-up assistmember 60 may be folded up, whereby the climb-up assist member 60 can bemore compactly arranged, and the climb-up assist member 60 can beprevented from coming in contact with equipment or the like installed inthe lower middle portion of the work vehicle 1 regardless of theelevation position of the mower unit 21 with respect to the work vehicle1.

The folding climb-up assist member 60 may be configured to enableattachment and detachment with respect to the mower unit 21 through theinsertion and withdrawal of the support shaft 78, and so that theclimb-up assist member 60 is accommodated in an accommodating partprovided to the work vehicle 1.

[20] A plurality of anti-slip parts shaped as a horizontal line whenviewed from above, a peak as viewed from above, an inverted peak asviewed from above, an upside-down check mark as viewed from above, or aninverted upside-down check mark as viewed from above for preventingslipping of the wheels 8, 11 may be formed so as to protrude upward inthe inclined surface 60A of the climb-up assist member 60. A pluralityof anti-slip parts having different shapes may also be formed so as toprotrude upward in the inclined surface 60A (*2) of the climb-up assistmember 60. Furthermore, an upward-protruding member may be welded to theinclined surface 60A (*2) of the climb-up assist member 60 to form ananti-slip part.

[21] As shown in FIG. 19, the climb-up assist member 60 may beconfigured to have a step part 60M set to a lower height than the upperpart of the mower unit 21 to assist the climbing up of the wheels 8, 11with respect to the mower unit 21, wherein one end part 60N of the steppart 60M is detachably engaged with the folded part 37E of the mowerdeck 37.

In this configuration, a connecting means 61 for detachably connectingthe climb-up assist member 60 to the mower unit 21 in the serviceposition in which the step part 60M assists the climbing up of thewheels 8, 11 with respect to the mower unit 21 is composed of the foldedpart 37E of the mower deck 37 as well as an one end part 60N of the steppart 60M in the climb-up assist member 60.

During climbing over the mower unit 21, the left and right wheels 8, 11climb up to the mower unit 21 from the step part 60M after climbing ontothe corresponding step part 60M at a low height. The left and rightwheels 8, 11 thereby climb over the mower unit 21 more easily than in acase in which the left and right wheels 8, 11 climb directly from theground surface to the mower unit 21.

Even when the mower unit 21 is pushed away from the climb-up assistmembers 60 by the left and right wheels 8, 11 when the left and rightwheels 8, 11 climb from the step parts 60M of the corresponding climb-upassist members 60 to the mower unit 21, the mower unit 21 is preventedfrom moving along with the climb-up assist members 60, whose movement isprevented by the pressure of the left and right wheels 8, 11. Thesmoothness of climbing over the mower unit 21 can therefore be preventedfrom being adversely affected by separation of the mower unit 21 fromthe climb-up assist members 60.

In this configuration, a plurality of anti-slip parts for preventingslipping of the wheels 8, 11 may be provided in protruding fashion onthe upper surfaces of the step parts 60M.

[22] As shown in FIG. 20, the climb-up assist member 60 may be formed soas to have a travel surface 60P on which the wheels 8, 11 travel whenthe wheels 8, 11 climb over the mower unit 21, and to have an uprightpart 60Q that is engaged inside the mower deck 37 so as to act on thelower edge 37D of the mower deck 37 from the inside of the mower deck 37in the service position.

In this configuration, the left and right wheels 8, 11 climb over themower unit 21 while travelling on the travel surfaces 60P of theclimb-up assist members 60 during climbing over the mower unit 21. Whenthe mower unit 21 is pushed away from the climb-up assist members 60 bythe left and right wheels 8, 11 in a process in which the left and rightwheels 8, 11 climb over the mower unit 21, the lower edge 37D of themower deck 37 comes in contact with the upright parts 60Q of theclimb-up assist members 60 that are prevented from moving by thepressure of the left and right wheels 8, 11, and the mower unit 21 isprevented from being pushed away from the climb-up assist members 60.This configuration prevents the possibility of adverse effects on theease of climbing over the mower unit 21 due to separation of the mowerunit 21 from the climb-up assist members 60.

In this configuration, a plurality of anti-slip parts for preventingslipping of the wheels 8, 11 may be provided in protruding fashion tothe travel surfaces 60P.

[23] As shown in FIG. 21, the second connecting means for detachablyattaching the climb-up assist members 60 in the storage position to themower unit 21 may have a cylinder member 80 provided with a hole 80A.The cylinder member 80 is secured by welding or another publicly knownmethod to the rear wall 39C of the transmission cover 39, or to theceiling wall 39A of the mower deck 37. The climb-up assist member 60 hasa bar member 60R that is inserted into the hole 80A. The bar member 60Ris secured to the lower surface of the climb-up assist member 60 bywelding or another publicly known method. The climb-up assist member 60is secured to the mower unit 21 by insertion of the bar member 60R intothe hole 80A. After the bar member 60R is inserted into the hole 80A, abeta pin 60S is inserted into a horizontally extending hole 60S that isprovided to the bar member 60R, whereby the bar member 60R is preventedfrom escaping the hole 80A. The beta pin 60S is connected to theclimb-up assist member 60 by wire or another publicly known means.

Two or more each of the cylinder member 80 and the bar member 60R mayalso be provided.

[24] As shown in FIGS. 22 and 23, the second connecting means fordetachably fixing the climb-up assist member 60 to the mower unit 21 inthe storage position may have a protrusion 82 provided to the rear wall39C of the transmission cover 39. A support member 84 is secured to theceiling wall 39A of the mower deck 37 in a position to the rear of therear wall 39C of the transmission cover 39. The support member 84 has apair of foot parts 84A, and a horizontal member 84B for connecting theupper ends of the foot parts 84A.

A hole 60T that allows passage of the protrusion 82 is formed in thefront surface of the climb-up assist member 60. As shown in FIG. 23, abracket 60W having a vertically extending portion is secured to thelower surface of the climb-up assist member 60 by welding or anotherpublicly known method. A pair of leaf springs 60U is attached to thefront surface of the vertically extending portion of the bracket 60W.Each of the leaf springs 60U engages with the horizontal member 84B ofthe support member 84, and a concave part for maintaining thisengagement is formed.

The protrusion 82 is inserted into the hole 60T of the climb-up assistmember 60, and the pair of leaf springs 60U engages with the horizontalmember 84B of the support member 84, whereby the climb-up assist member60 is detachably retained with respect to the mower unit 21. Detachmentfrom the protrusion 82 of the climb-up assist member 60 may then beprevented by inserting the beta pin 60S into the hole 82A of theprotrusion 82.

Two or more each of the protrusion 82 and the corresponding hole 60T maybe provided.

[25] As shown in FIGS. 24 through 26, a climb-up assist member 160 issecured to the rear wall 39C of the transmission cover 39, whereby thisposition can be set as the service position of the climb-up assistmember 160.

The climb-up assist member 160 as an extending part that extends to therear towards the rear end part of the mower deck 37 is welded to therear wall 39C of the transmission cover 39. Each climb-up assist member160 has an inclined portion 160A that gradually tilts downward and tothe rear towards the rear end part of the mower deck 37 from the ceilingwall 39A of the transmission cover 39, and the rear end part 160Bpositioned in the vicinity of the rear end part of the mower deck 37 isformed in bent fashion so as to protrude upward. A pair of left andright foot parts 162 that make contact with the upper surface of themower deck 37 when the transmission cover 39 is attached to the mowerdeck 37 are welded to the back surface of the inclined portion 160A ineach climb-up assist member 160.

In a case in which the mower unit 21 is attached to the lower middleportion of the tractor 1 from this configuration, when the tractor 1 ismoved forward so that the left and right front wheels 8 face towards theleft and right climb-up assist members 160 provided to the mower 21, theleft and right front wheels 8 catch upon reaching the rear end parts160B of the corresponding climb-up assist members 160, and the mowerdeck 37 can be rapidly climbed up in a state in which slipping withrespect to the mower deck 37 is prevented by this catching. When theforward motion of the tractor 1 is continued after this climbing, theleft and right front wheels 8 ascend the inclined portions 160A of thecorresponding climb-up assist members 160, climb up the transmissioncovers 39, transfer from the transmission covers 39 to the front upperpart 37A of the mower deck 37, and descend onto the ground surface fromthe front upper part 37A of the mower deck 37. Through this operation,the mower unit 21 can be positioned between the left and right frontwheels 8 and the left and right rear wheels 11 in the tractor 1, and themower unit 21 can be attached to the lower middle portion of the tractor1.

In the case of detaching the mower unit 21 from the lower middle portionof the tractor 1, when the tractor 1 is moved forward after releasingthe attachment of the mower unit 21 to the tractor 1, the left and rightrear wheels 11 catch upon reaching the rear end parts 160B of thecorresponding climb-up assist members 160, and the mower deck 37 can berapidly climbed up in a state in which slipping with respect to themower deck 37 is prevented by this catching. When the forward motion ofthe tractor 1 is continued after this climbing, the left and right rearwheels 11 ascend the inclined portions 160A of the correspondingclimb-up assist members 160, climb up the corresponding transmissioncovers 39, transfer from the transmission covers 39 to the front upperpart 37A of the mower deck 37, and descend onto the ground surface fromthe front upper part 37A of the mower deck 37. Through this operation,the mower unit 21 can be positioned behind the tractor 1.

In other words, by implementing the simple and inexpensive modificationof merely providing the climb-up assist members 160 to the left andright transmission covers 39, the rear end portions 160B of the left andright climb-up assist members 160 can be made to function as anti-slipmembers for preventing the wheels 8, 11 of the tractor 1 from slippingwhen the mower 21 is attached and detached with respect to the lowermiddle portion of the tractor 1. Since the inclined portions (front sideportions) 160B positioned further forward than the rear end parts 160Bin the climb-up assist members 160 smoothly connect so that there is nodifference in level between the mower deck 37 and the transmissioncovers 39, the left and right front wheels 8 or the left and right rearwheels 11 can be made to rapidly climb over the mower 21 merely bymoving the tractor 1 forward. As a result, there is no need for themanual labor of carrying the mower 21 to the lower middle portion of thetractor 1, or of carrying the mower 21 out from the lower middle portionof the tractor 1, and the positional relationship between the tractor 1and the mower unit 21 can be easily and appropriately modified.

A conventional mower (not shown) in which a conventionally structuretransmission cover (not shown) not provided with a climb-up assistmember 160 is attached can be easily and inexpensively modified to aclimbable configuration that allows climbing over by the tractor 1,merely by replacing the conventionally structured transmission coverdetachably attached to the upper part of the mower deck 37 with thetransmission cover 39 based on the present invention, so as tofacilitate maintenance of the transmission mechanism 38 while preventingadherence of cut grass and the like to the transmission mechanism 38 fordriving the cutting blades that is provided to the upper part of themower deck 37, in the same manner as the transmission cover 39 based onthe present invention.

As shown in FIGS. 26 and 27, when the transmission covers 39 areattached to the mower deck 37, pairs of engaging tabs 63 on the left andright for joining with the upper surface of the front end parts in theceiling walls 39A of the corresponding transmission covers 39 are weldedto the front upper part 37A of the mower deck 37. According to thisconfiguration, the front ends of the transmission covers 39 can bereliably prevented from rising up from the front upper part 37A of themower deck 37 due to recoil when the wheels 8, 11 of the tractor 1 catchin the rear end parts 160B of the left and right climb-up assist members160 and climb up, and damage to the engaging fixture 57 and otherproblems caused by this uprising can be prevented.

In the left and right transmission covers 39 as shown in FIGS. 25through 27, round bar members 65 are welded in a left-right orientationin positions below the engaging parts 57B in the ceiling walls 39A. Theengaging parts 57B can thereby be prevented from deforming due topressure on the engaging parts 57B when the wheels 8, 11 of the tractor1 transfer from the transmission covers 39 to the front upper part 37Aof the mower deck 37, and the engagement of the engaging parts 57B withthe engaged fixtures 56 can be prevented from being released by thisdeformation.

[26] The climb-up assist members 160 may be detachably connected to thetransmission covers 39 by bolts/nuts or the like.

[27] As shown in FIG. 29, the climb-up assist member 160 may beconfigured extending to the rear so as to conform to the upper surfaceof the mower deck 37 from the transmission cover 39 to the rear end partof the mower deck 37.

[28] As shown in FIG. 30, the climb-up assist member 160 may beconfigured to have a rear portion 160C that extends further to the rearfrom the anti-slip portion 160B formed in the vicinity of the rear endpart of the mower deck 37, and so that the rear portion 160C is formedin a manner in which this portion tilts downward and to the rear fromthe anti-slip portion 160B. In this configuration, when the rear portion160C is configured to elastically deform from a state of separation fromthe ground surface (see FIG. 30A) to a state of contact with the ground(see FIG. 30B) in conjunction with the pressure of the wheels 8, 11,damage to the landscape due to ground contact of the rear portion 160Ccan be prevented during mowing, and the front end sides of thetransmission covers 39 can be more reliably prevented from rising upfrom the front upper part 37A of the mower deck 37 due to recoil whenthe wheels 8, 11 climb up on the climb-up assist members 160 duringclimbing by the work vehicle 1.

[29] Various modifications may be made to the numerical quantity, shape,and other characteristics of the anti-slip portions 160B in the climb-upassist members 160. For example, a plurality of anti-slip portions 160Bshaped as a horizontal line when viewed from above, a peak as viewedfrom above, an inverted peak as viewed from above, an upside-down checkmark as viewed from above, or an inverted upside-down check mark asviewed from above may be formed so as to protrude upward in the climb-upassist members 160. A plurality of anti-slip portions 160B havingdifferent shapes may also be formed so as to protrude upward in theclimb-up assist members 160. Furthermore, an anti-slip portion 160B maybe formed in a climb-up assist member 160 by welding a separate memberso as to protrude upward.

1. A mower unit configured to be attached at a position between frontwheels and rear wheels of a work vehicle comprising: a mower deck; atleast one blade supported by the mower deck; a transmission mechanismfor driving the blade provided to project from a ceiling area of themower deck; and a climb-up assist comprising a transmission covercovering the transmission mechanism from above and forming a ceilingwall over the transmission mechanism, wherein the climb-up assistfurther comprises a guide member secured at least to the transmissioncover and a climb-up assist member is slidably and pivotally engagedwith the guide member such that the climb-up assist member is movablefrom a storage position atop the mower deck to a service positioninclined from the mower deck to the ground, and wherein the climb-upassist member comprises an engaging pin seated in a slit defined in theguide member to enable sliding and pivotal movement of the climb-upassist member relative to the guide member.
 2. A mower unit configuredto be attached at a position between front wheels and rear wheels of awork vehicle as claimed in claim 1, wherein the climb-up assist furthercomprises a reinforcing member for the ceiling wall provided upright atand upward from an upper surface of the ceiling wall to extend from afront of the ceiling wall to a rear of the ceiling wall, and wherein thereinforcing member is affixed to an inner end of the ceiling wall, toprevent the wheels having climbed over the ceiling wall from slippingoff the ceiling wall in a transverse direction of the vehicle.
 3. Amower unit configured to be attached at a position between front wheelsand rear wheels of a work vehicle as claimed in claim 1, wherein theclimb-up assist member is secured in the storage position by a pinpassing through the guide member to engage an engaging hole in theclimb-up assist member.
 4. A mower unit configured to be attached at aposition between front wheels and rear wheels of a work vehicle asclaimed in claim 1, wherein the climb-up assist member is secured in theservice position by a pin passing through the guide member to engage anengaging hole in the climb-up assist member.
 5. A mower unit configuredto be attached at a position between front wheels and rear wheels of awork vehicle as claimed in claim 1, wherein the slit defines an openingto permit removal of the engaging pin therefrom and detachment of theclimb-up assist member from the guide member.
 6. A mower unit configuredto be attached at a position between front wheels and rear wheels of awork vehicle as claimed in claim 1, wherein the guide member is securedto the mower deck.